| 摘要 |
<p>Neutral radiation, esp. soft gamma rays and X-rays, is detected and localised by (a) causing it to collide with a gas in an enclosure to produce photoelectrons, (b) applying an electric field to the enclosure to cause the photoelectrons to drift to a second electric field which is strong enough to produce secondary photons by exictation-relaxation, and nc) analysing the energy of these photons, pref. using a layer of material which converts them to near UV or visible scintillations and finding the bary-centre with the help of an analogue or digital computer. The detector consists of a sealed enclosure with a window for the radiation at one end and contg. a gas, esp. a noble gas and two sets of electrodes for producing the fields. The analysis appts. for step (C) pref. includes photomultiplier tubes. The process is esp. for medical use. Satisfactory spatial resolution is achieved together with much higher energy resolution than was previously possible except with solid state scintillators such as gamma cameras. The present device can scan much larger areas than these solid scintillators.</p> |
